The present invention relates generally to motor drives units and, more particularly, to a motor control unit configured to control operation of any of a variety of permanent magnet motors using a torque-per-current relationship developed using motor parameters normalized with respect to demagnetization current of a motor at approximately maximum torque. Accordingly, it is not necessary to optimize each motor drive unit for the particular motor associated therewith.
There are a variety of applications that require a motor to deliver constant power or torque over a wide operational range. Permanent magnet (PM) synchronous motors have often been utilized in such applications because, by properly adjusting the combination of magnetic saliency and permanent magnet flux in the PM motor design, the motor can achieve very high sustainable constant torque outputs.
However, in order to maximize or optimize output of the PM motor, for example, under torque control, knowledge of the motor must be assembled and then used to configure the motor control unit coupled with the particular PM motor. Such configuration and design can be rather costly, particularly, when compounded over many PM motors, for example, both internal PM motors and surface PM motors, and a variety of motor control units.
Therefore, it would be desirable to have a system and method to allow a given motor control unit to improve control of a PM motor without significant, motor-specific configuration and optimization. In particular, it would be advantageous to have a system and method for universal adaptive torque control that is compatible with both internal and surface mount permanent magnet motors.